Answer:
a. The resonance effect of the hydroxyl group stabilizes the anionic intermediate
Explanation:
The resonance effect stabilizes the the charge through the delocalization of the pi bonds. The resonance stabilization mainly occurs in the conjugated pi systems.
For example, phenol forms a strong hydrogen bonds than the nonaromatic alcohols as the [tex]$O_2-H_2$[/tex] dipole present in the hydroxyl group is being stabilized by the presence of the aromatic ring of phenol.
Thus the resonance effect of the hydroxyl group stabilizes the anionic intermediate.